4/2017 AER Watkins Glen race
Goal was to just finish the race incident free. We were all unsure as to where the car would class since there’s a large disparity in lap time potential between driver pairs. We all really wanted to be in class 4 with this car, but after Friday’s qualifying session we put the car into class 5 with the 7th fastest lap time. 2 of the 4 drivers are in the 2:10.xxx range and the other 2 are 5-7 seconds slower per lap. It’s something we need to work on. The car is essentially a class “4.5” car in this race.
Heading out:
Green flag! There we are on the right...
Crazy race start with one of Team Sahlen’s Cayman’s wrecking right at the drop of the green flag and almost causing a huge pile up. My first 2 wide rolling start also. If you have extra time, the first 12 laps or so there’s some good battling:
https://youtu.be/si_yyScV4Vk
We were about mid-pack in class 5 and 7th place overall with the 3rd driver in the car when divine intervention came down upon him/us and prevented a giant wreck. Nothing like starting a spin at 106mph and not touch a single piece of armco at a track where it’s only feet off the asphalt (must watch!):
https://youtu.be/zhCCTJzI7Ec
That essentially parked us for the rest of the day as we went over the car to make sure everything was all right. We lost a tire from dirt packing into the wheel from going slideways in the grass and coincidentally (or not) one of the lower front coilover locking collars worked loose so that was clunking around. We also put in some fresh Redline 75w-110 diff fluid because it was starting to get noisy and extra clunky. The PO used Redline “NS” gear oil that had no friction modifier so it was always very noisy.
We went back out on track for a few more laps at the end of the day to make sure everything was ok for Sunday. We found that the 6th gear synchro was also starting to take a sh!t.
Sunday: The cooling system was gradually getting more and more heat soaked as we cycled through drivers. Driver 2 was the first to report higher water temps vs Saturday. By the time I got in as 4th driver the water temp was dangerously high to run for extended period. Within 5 laps I started seeing temp spikes to 240*F. Once I realized I couldn’t get them to come down by farting around I parked it. The rest of the day was trying to bleed the coolant system and trying to determine if we had a slight head gasket leak. VQ’s are notorious for finicky coolant systems to bleed.
Subpar results for our first race. Positives are that we ran as high as 5th overall for awhile and we had the 7th fastest lap overall for the weekend. Oh, and the car came out unscathed in that spin!!
A few things that needed addressing before the next race
1) the 4.08 final with a 6800rpm rev limit is too short, especially for the Glen.
2) the car couldn’t brake as well as the BMW’s.
3) the CD009 6th gear synchro was toast.
4) the 4 piston Wilwood superlites with equal piston sizing have serious pad taper issues.
Here’s what was a brand new set of Hawk DTC-60 at the start of the weekend after 14ish hours of track time. Maybe this is why braking felt ‘meh’ over the course of the weekend?:
It had to be addressed for the next race, which was 4 weeks later at New Jersey Motorsports Park (NJMP) so onto prep time.
First thing was testing if the head gasket was leaking. Compression and leak down tests were good. Just to be certain we used this nifty little tool that “sniffs” the gas in the radiator for CO2 and changes color if it does, which indicates a leak of combustion gases. Luckily it tested negative:
https://www.amazon.com/UVIEW-560000-.../dp/B000NPDL76
It was air in the system that came to ruin our Sunday at Watkins Glen. VQ’s are notoriously a PITA to bleed. Most VQ swaps do away with the OEM bleeder that ties into a line that runs from behind the T-stat to the heater core circuit. This is a problem. Also a problem that the top of the radiator in a S-chassis is far below the high points of the VQ cooling system.
We T’d in a generic bleeder in the highest line of the system that runs from the radiator return to behind the t-stat.
Then bought this vacuum coolant refill tool to help evacuate much of the air in the system:
https://www.amazon.com/Robinair-7526...nt+refill+tool
And lastly, a giant funnel with the nose of the car way up in the air.
https://www.amazon.com/EPAuto-Radiat...ill+tool&psc=1
It all worked and we haven’t had bleeding/overheating problems since.
After chatting with Def on here about the brake situation, I went all in on making radial mount brackets for the Wilwood FSL6R’s based on his design. I changed a few things for manufacturability and also made them so they will fit 12.2” rotors as is and 12.8” rotors with a spacer:
Machining:
Ready for testing:
Perfect:
Also changed the final drive to an S15 3.69 ring and pinion. Many people just swap ring and pinions using existing pinion height shims and side bearing spacers, etc. Definitely couldn’t get away with that here. Look at how different the pinons are:
4.08 on left, 3.69 on right:
I ended up having to grind down the pinion height shim that came with the 3.69 substantially. See/read more detail in this thread if you’d like:
http://www.nissanroadracing.com/show...?t=5069&page=3
I also decided to move away from Hawk pads and try a different brake pad compounds. Ended up going with Porterfield/Raybestos ST-43 compound for the front and rear after talking with many endurance guys. They had to make the rear Z32 pad shape custom (more on this next).